<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
      xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
    <meta charset="UTF-8"/>
    <title>单文件上传(HTML5 实现进度读取)</title>
</head>

<script>
    function fileSelected() {
        var file = document.getElementById('fileToUpload').files[0];
        if (file) {
            var fileSize = 0;
            if (file.size > 1024 * 1024)
                fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB';
            else
                fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB';

            document.getElementById('fileName').innerHTML = 'Name: ' + file.name;
            document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize;
            document.getElementById('fileType').innerHTML = 'Type: ' + file.type;
        }
    }

    function uploadFile() {
        var xhr = new XMLHttpRequest();
        var formObj = document.getElementById("form1");
        var fd = new FormData(formObj);

        /* event listners */
        xhr.upload.addEventListener("progress", uploadProgress, false);
        xhr.addEventListener("load", uploadComplete, false);
        xhr.addEventListener("error", uploadFailed, false);
        xhr.addEventListener("abort", uploadCanceled, false);
        /* Be sure to change the url below to the url of your upload server side script */
        xhr.open("POST", "/file/singleFileUpload");
        xhr.send(fd);
    }

    function uploadProgress(evt) {
        if (evt.lengthComputable) {
            var percentComplete = Math.round(evt.loaded * 100 / evt.total);
            document.getElementById('progressNumber').innerHTML = percentComplete.toString() + '%';
        }
        else {
            document.getElementById('progressNumber').innerHTML = 'unable to compute';
        }
    }

    function uploadComplete(evt) {
        /* This event is raised when the server send back a response */
        alert(evt.target.responseText);
    }

    function uploadFailed(evt) {
        alert("There was an error attempting to upload the file.");
    }

    function uploadCanceled(evt) {
        alert("The upload has been canceled by the user or the browser dropped the connection.");
    }
</script>
<body>
<h1 th:inlines="text">文件上传</h1>
<form id="form1" method="post" enctype="multipart/form-data">
    <div class="row">
        <label for="fileToUpload">Select a File to Upload</label>
        <input type="file" name="fileName" id="fileToUpload" onchange="fileSelected();"/>
    </div>
    <div id="fileName"></div>
    <div id="fileSize"></div>
    <div id="fileType"></div>
    <div class="row">
        <input type="button" onclick="uploadFile()" value="Upload"/>
    </div>
    <div id="progressNumber"></div>
</form>
</body>
</html>